The more precise determination of radiation dose received by humans in diverse situations is the ultimate objective of the proposed research. In terms of accuracy, reliability, and convenience, ionization chambers afford the best means of dosimetric measurements. Special conducting plastics are needed for the accurate dosimetry of photons, neutrons, electrons, and heavy ions by the ionometric method. The further understanding of materials in current use for this purpose and the development of improved formulations represent the principal thrust of the proposed program. A standard of absorbed dose presently does not exist though the need for such is ever increasing. A dose standard requires a reference material. Various substances are to be considered to serve this purpose. Ionization chambers will be studied in all of their ramifications including procedures, necessary ancillary apparatus, and interpretation of ionization currents.